Urethral catheters have generally been used for four purposes: to relieve urinary retention, to test residual urine, to obtain urine directly from the bladder for diagnostic purposes, and for bladder lavage, instillations or other therapeutic reasons.
Out of the four purposes listed above, catheters are no longer needed for testing residual urine, nor to obtain urine directly from the bladder.
The use of a cathether for therapeutic purposes, such as bladder instillation, is essential, but in such cases a catheter is introduced for a short period of time and is removed shortly after it has been inserted, so the patient suffers relatively little discomfort. The same may be said for the use of a catheter after bladder or prostatic surgery.
The main reason for which catheters are left indwelling for weeks or months is for relief of urinary retention, most often because of infravesical prostatic obstruction.
In many instances an indwelling catheter has to be left for an extended period of time because the patient is not fit for surgery, or the condition of the patient requires that surgery should be postponed. Unfortunately, there is often a waiting list of patients for prostatectomy, many of whom must endure an indwelling catheter for weeks or even months.
An indwelling catheter is not only a common cause of urinary tract infection, urethral inflammation and discharge, possible urethral strictures and many other complications, but is also a serious psychological problem. Most men with an indwelling catheter feel they lose dignity, are unable to perform sexually, and are often unable to continue their routine life. They have to suffer all this in addition to the local discomfort caused by the catheter irritating the entire length of the urethra, in spite of the fact that only a short length of a few centimeters is needed to overcome the obstruction.
Only one alternative for an indwelling urethral catheter has been tried till now. This is an iron, gold-coated spiral known as PROSTAKAT (TM).
The intraurethral catheter of the present invention is a simpler and more physiological prosthesis and is easier to insert into the prostatic urethra, easier to remove, and much more economical in comparison to the gold-coated spiral.
A catheter for use in internal biliary drainage, known as the Miller double mushroom biliary stent, is also known wherein a double mushroom design helps maintain the stent position. These Miller stents come in diameter sizes of 10.0, 12.0 and 14.0 French.